Add XCB supportHEADmaster

This adds an XCB backend and hooks it up for cairo (not skia... yet).
This is for doing performance comparisons of the GL backend against
"standard Cairo".

1 files changed, 117 insertions, 0 deletions

diff --git a/src/xcb.cpp b/src/xcb.cpp
new file mode 100644
index 0000000..4de34da
--- /dev/null
+++ b/src/xcb.cpp
@@ -0,0 +1,117 @@
+/*
+ * Copyright 2017 © Samsung Research America, Silicon Valley
+ *
+ * Use of this source code is governed by the 3-Clause BSD license
+ * specified in the COPYING file included with this source code.
+ */
+#include <config.h>
+
+#include <err.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "xcb.h"
+#include "device_config.h"
+
+bool
+createXCBContextAndWindow(xcb_state_t *state, int width, int height)
+{
+    xcb_screen_t *screen;
+    uint32_t mask[2];
+    const xcb_setup_t *setup;
+    xcb_visualtype_t *visual;
+    xcb_generic_event_t *event;
+    xcb_screen_iterator_t screen_iter;
+    xcb_depth_iterator_t depth_iter;
+
+    // Set up XCB
+    state->xcb_connection = xcb_connect(NULL, &state->xcb_screen_number);
+    if (state->xcb_connection == NULL) {
+        warnx("Could not create XCB context\n");
+        return false;
+    } else if (xcb_connection_has_error(state->xcb_connection)) {
+        warnx("Could not connect to X11 server\n");
+        return false;
+    }
+
+    // Set up screen
+    setup = xcb_get_setup(state->xcb_connection);
+    if (setup == NULL) {
+        warnx("Could not create XCB setup\n");
+        return false;
+    }
+    screen_iter = xcb_setup_roots_iterator(setup);
+    for (; screen_iter.rem; --state->xcb_screen_number, xcb_screen_next(&screen_iter)) {
+        if (state->xcb_screen_number == 0) {
+            state->xcb_screen = screen_iter.data;
+            break;
+        }
+    }
+    if (state->xcb_screen == NULL) {
+        warnx("Could not create XCB screen\n");
+        return false;
+    }
+
+    // Create window
+    state->xcb_window = xcb_generate_id(state->xcb_connection);
+    mask[0] = 1;
+    mask[1] = XCB_EVENT_MASK_EXPOSURE;
+    xcb_create_window(state->xcb_connection,             // XCB connection to X11
+                      XCB_COPY_FROM_PARENT,           // Window's depth
+                      state->xcb_window,              // Window ID
+                      state->xcb_screen->root,        // Parent window
+                      20, 20,                         // X, Y position
+                      width,                          // Window width
+                      height,                         // Window height
+                      0,                              // Border width in pixels
+                      XCB_WINDOW_CLASS_INPUT_OUTPUT,  // Behavior class for window
+                      state->xcb_screen->root_visual, // New window's visual id
+                      XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK,  // Mask type
+                      mask);                          // Mask values list
+    xcb_map_window(state->xcb_connection, state->xcb_window);
+    xcb_flush(state->xcb_connection);
+
+    // Get the visual
+    depth_iter = xcb_screen_allowed_depths_iterator(state->xcb_screen);
+    for (; depth_iter.rem; xcb_depth_next(&depth_iter)) {
+        xcb_visualtype_iterator_t visual_iter;
+
+        visual_iter = xcb_depth_visuals_iterator(depth_iter.data);
+        for (; visual_iter.rem; xcb_visualtype_next(&visual_iter)) {
+            if (state->xcb_screen->root_visual == visual_iter.data->visual_id) {
+                state->xcb_visual_type = visual_iter.data;
+                return true;
+            }
+        }
+    }
+
+    warnx("XCB internal error, could not find visual\n");
+    xcb_disconnect(state->xcb_connection);
+    return false;
+}
+
+void
+destroyXCBContextAndWindow (xcb_state_t *state)
+{
+    xcb_disconnect(state->xcb_connection);
+}
+ 
+void
+cleanup_state_xcb (void *data)
+{
+    xcb_state_t *state = (xcb_state_t*)data;
+    destroyXCBContextAndWindow(state);
+    free(state);
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :